$ docker build -t dockly . Sending build context to Docker daemon 16.52MB Step 1/9 : FROM node:8-alpine Get https://registry-1.docker.io/v2/library/node/manifests/8-alpine: unauthorized: incorrect username or password $ docker login Authenticating with existing credentials... Stored credentials invalid or expired Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one. Username (XXXXXX): WARNING! Your password will be stored unencrypted in /root/.docker/config.json. Configure a credential helper to remove this warning. See https://docs.docker.com/engine/reference/commandline/login/#credentials-store Login Succeeded